The present invention relates to a fixing apparatus for fixing a toner image transferred to a sheet in an electrophotogaphic apparatus.
This kind of fixing apparatus is equipped with a fixing roller and a pressure applying roller set in pressure contact with the fixing roller. A sheet carrying a toner image is fed into, and passed through, an area between the fixing roller and the pressure applying roller and, by doing so, heated under pressure to allow the image to be fixed to the sheet.
Incidentally, the fixing roller has a heater at its inside and is heated thereby. If, however, the fixing roller is heated from within, a longer time is required until the outer surface of the fixing roller is raised to an operational temperature, thus involving a disadvantage.
In recent times, a fixing apparatus has been developed in which a heating roller is provided in a position spaced-apart from the fixing roller and a heat transmitting belt is spanned between the heating roller and the fixing roller. In this fixing apparatus, the heat generated at the heating roller is transmitted through the heat transmitting belt to the outer surface of the fixing roller to achieve direct heating. It is, therefore, possible to raise its temperature to an operational level in a shorter period of time.
In the prior art, a space defined by the fixing roller, heating roller and heat transmitting belt is formed in an opened state toward an outside, so that the air warmed in the space is discharged to the outside. This lowers the heating efficiency of the heat transmitting belt and largely dissipates electric power. It therefore takes longer to start the fixing apparatus.
It is accordingly the object of the present invention to provide a fixing apparatus which can improve the heating efficiency of a heat transmitting member by keeping the air present in a space defined by the fixing roller, heating roller and heat transmitting member from being discharged.
The fixing apparatus of the present invention comprises a fixing roller arranged opposite to a heating roller in a spaced-apart relation, a heat transmitting member spanned between the fixing roller and the heating roller and adapted to be run in a continuous manner to transmit heat from the heating roller to the fixing roller, a pressure applying roller set in pressure contact with the fixing roller through the heat transmitting member to heat a to-be-fixed material, by the fixing roller, under pressure, and blocking members for blocking openings at those opposite sides of a space defined by the fixing roller, heating roller and heat transmitting member.
The fixing apparatus of the present invention comprises a fixing roller arranged opposite a heating roller in a spaced-apart relation, a heat transmitting member spanned between the fixing roller and the heating roller and adapted to be run in a continuous manner to transmit heat from the heating roller to the fixing roller, a pressure applying roller set in pressure contact with the fixing roller through the heat transmitting member to heat a to-be-fixed material, by the fixing roller, under pressure, blocking members for blocking openings at those opposite sides of a space defined by the fixing roller, heating roller and heat transmitting member, and a drive device for moving the blocking members in a direction perpendicular to the running direction of the heat transmitting member.
The fixing apparatus of the present invention comprises a fixing roller arranged opposite to a heating roller in a spaced-apart relation, a heat transmitting member spanned between the fixing roller and the heating roller and adapted to be run in a continuous manner to transmit heat from the heating roller to the fixing roller, a A pressure applying roller set in pressure contact with the fixing roller through the heat transmitting member to heat the to-be-fixed material, by the fixing roller, under pressure, blocking members for blocking openings at those opposite sides of a space defined by the fixing roller, heating roller and heat transmitting member, and a drive device for moving the blocking members in a direction perpendicular to the running direction of the heat transmitting member, and a cooling fan provided at outer sides of the respective blocking members.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.